Franckh-Kosmos Verlags-GmbH & Co. KG, Pfizerstr. 5-7, 70184 Stuttgart, Germany | +49 (0) 711 2191-0 | www.kosmos.de Thames & Kosmos, 301 Friendship St., Providence, RI, 02903, USA | 1-800-587-2872 | www.thamesandkosmos.com Thames & Kosmos UK Ltd, Goudhurst, Kent, TN17 2QZ , United Kingdom | 01580 212000 | www.thamesandkosmos.co.uk

KIT CONTENTS

CoverSaucerSpeaker coverDome

SpeakerOn-off switchCircuit boardScrews (8)

YOU WILL ALSO NEED: Two AA batteries (1.5-volt, type AA/LR6), small Phillips head (cross-head) screwdriver

1234

5678

Greetings, Earthlings!Everyone knows what an alien flying saucer is, and everyone has their own idea about what one should look like — despite the fact that nobody has actually ever seen one. Still, the idea of visitors from other another planet inspires our fantasies. And who knows? Maybe one day we really will have a close encounter of the “third kind.” Until then, you can use this experiment kit to build your own UFO and send musical messages into outer space. These instructions will show you how to do it. So let’s get going!

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Hi! I’m Matrix!

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GEEKOUT! WHAT’S A

THEREMIN? The Musical UFO is based on an invention known as the theremin. That’s a musical instrument that, like the UFO, can be played without actually touching it with your hands. Instead of responding to light, though, the theremin reacts to the electrical capacitance inside every human body. This influences the theremin’s electromagnetic field, which then produces sounds.

The theremin gets its name from its Russian inventor, Leon Theremin. His invention was the inspiration for other electronic instruments such as the synthesizer, without which today’s electronic music would be inconceivable. A theremin that responds to light is also known as a photo-theremin. For decades, theremins have been used in science fiction and horror movie soundtracks. This is why their unique sound is associated with the eerie sounds of UFOs and monsters. Today, theremins are used by many rock, electronic, and concert musicians.

Leon ThereminTheremins have been

custom built in many

shapes and sizes

My favorite

instrument!

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To really understand how the Musical UFO works, you need to understand how four important electronic components work: the phototransistor (which is a type of transistor), the integrated circuit, the speaker, and the capacitor.

HOW DO THE UFO’S ELECTRONICS WORK?

GEEKOUT!

THE TRANSISTOR A transistor is a semiconductive device, meaning that

it conducts different amounts of electrical current

under different conditions. A transistor has three

terminals. Differing current on one terminal changes

the amount of current that can flow through the other

two terminals.

There are many different types of transistors, but

to understand how they work, let’s explore two of them:

NPN and PNP transistors.

In an NPN transistor, when a current 1 flows into

the base terminal B , it allows current 2 to move

through the other two terminals, from the collector C

to the emitter E . If there is no current at the base, no

current will flow through the collector to the emitter.

In a PNP transistor, when a current 1 flows out

of the base terminal, it allows current 2 to move from

the emitter to the collector.

An NPN transistor is a sandwich of “p” material

between two layers of “n” material. A PNP is the

opposite: “n” material sandwiched between two layers

of “p” material. The “n” zone contains mobile electrons

(shown here in green), while the “p” zone contains

empty spaces, or holes. Between the zones, there are

thin boundaries that normally block the current flow,

since the electrons are attaching themselves to the

holes there. When electrons either flow into or out of

the base, they allow electrons to cross the boundaries,

opening up the flow of current.

E C

B1

2

C E

B1

2

NPN

PNP

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